Sharpening circular saws with your own hands

Material and properties of carbide teeth

In domestic saws, sintered tungsten-cobalt alloys of grades VK (VK6, VK15, etc.) are used as the material for cutting inserts. BK6 has a hardness of 88.5 HRA, BK15. 86 HRA. Foreign manufacturers use their own alloys. Hard alloys VK consist mainly of cobalt cemented tungsten carbide. The characteristics of the alloy depend not only on its chemical composition, but also on the grain size of the carbide phase. The smaller the grain, the higher the hardness and strength of the alloy.

Attach the carbide plates to the disc by high-temperature brazing. As a material for soldering, at best, silver solders are used (PSr-40, PSr-45), at worst. copper-zinc solders (L-63, MNMTs-68-4-2).

Sharpening circular saws

Basic principles of sharpening

When sawing massive workpieces, the side edges are also subject to rapid wear.

The saw should not be excessively blunt. The radius of rounding of the cutting edge should not exceed 0.1-0.2 mm. In addition to the fact that when working with a very blunt saw, productivity drops sharply, sharpening it takes several times longer than sharpening a saw with a normal bluntness. The degree of bluntness can be determined both by the teeth themselves and by the type of cut they leave.

Correct sharpening of circular saws consists in ensuring the maximum number of sharpenings, which in the optimal case can reach 25-30 times, while ensuring the proper sharpness of the cutting edge. For this purpose, it is recommended to sharpen the carbide tooth on the front and back planes. In fact, the teeth can be sharpened along one front plane, but the number of possible sharpenings is almost two times less than when sharpening along two planes. The figure below illustrates why this is happening.

The last pass when sharpening saw blades is recommended to be done along the back plane of the tooth. Standard metal removal rate. 0.05-0.15mm.

Before sharpening, the saw must be free of dirt, such as resin, and the values ​​of the sharpening angles must be checked. On some saws they are written on the disc.

Carbide tooth geometry

The following types of teeth are distinguished by shape.

Straight tooth. Typically used in rip saws where quality is not critical.

Oblique (beveled) tooth with left and right angles of inclination of the posterior plane. Teeth with different angles of inclination alternate with each other, which is why they are called alternately cut. This is the most common tooth shape. Depending on the size of the sharpening angles, saws with alternating teeth are used for sawing a wide variety of materials (wood, chipboard, plastics). both in the longitudinal and transverse directions. Saws with a large flank angle are used as scoring saws when cutting double-sided lamination boards. Their use allows you to avoid coating chips at the edges of the cut. Increasing the bevel angle reduces the cutting force and reduces the risk of chipping, but at the same time reduces the tool life and strength of the tooth.

The teeth can have an inclination not only of the rear, but also of the front plane.

Trapezoidal tooth. A feature of these teeth is the relatively slow speed of bluntness of the cutting edges in comparison with alternating beveled teeth. They are usually used in combination with a straight tooth.

Alternating with the latter and slightly rising above it, the trapezoidal tooth performs a rough cut, and the straight one following it. fine. Saws with alternating straight and trapezoidal teeth are used for cutting boards with double-sided lamination (chipboard, MDF, etc.), as well as for sawing plastics.

Conical tooth. Tapered saws are auxiliary and are used to cut the lower layer of the laminate, preventing it from chipping when passing the main saw.

In the overwhelming majority of cases, the front face of the teeth is flat, but there are saws with a concave front face. They are used for fine cross-cutting.

Equipment and materials for sharpening saw blades

When using abrasive wheels (especially diamond), it is advisable to cool them with coolant.

As the temperature rises, the microhardness of abrasive materials decreases. An increase in temperature to 1000 ° C reduces the microhardness by almost 2-2.5 times compared to the microhardness at room temperature. An increase in temperature to 1300 ° C causes a decrease in the hardness of abrasive materials by almost 4-6 times.

The use of water for cooling can lead to rust on the parts and assemblies of the machine. To eliminate corrosion, soap and certain electrolytes (sodium carbonate, soda ash, trisodium phosphate, sodium nitrite, sodium silicate, etc.) are added to the water, which form protective films. For normal sanding, soap and soda solutions are most often used, and for fine sanding. low-concentration emulsions.

However, when sharpening saw blades at home with a low intensity of sharpening work, they do not resort to cooling the wheel so often. not wanting to waste time on it.

To increase the productivity of sharpening with abrasive wheels and reduce specific wear, you should choose the largest grain size, which ensures the required surface cleanliness of the sharpened tooth.

To select the grit size of the abrasive, in accordance with the sharpening stage, you can use the table in the article about sharpening bars. For example, in the case of using diamond wheels, wheels with a grain size of 160/125 or 125/100 can be used for rough sharpening, for finishing. 63/50 or 50/40. Wheels with a grain size of 40/28 to 14/10 are used for chipping.

The peripheral speed of the wheel when sharpening carbide teeth should be about 10-18 m / s. This means that when using a circle with a diameter of 125 mm, the engine speed should be around 1500-2700 rpm. Sharpening of more brittle alloys is carried out at a lower speed from this range. When sharpening carbide tools, the use of hard modes leads to the formation of increased stresses and cracks, and sometimes to chipping of the cutting edges, while the wear of the wheel increases.

When using machines for sharpening circular saws, changing the relative position of the saw and the grinding wheel can be implemented in different ways. moving one saw (the motor with the wheel is stationary), the simultaneous movement of the saw and the motor, only the movement of the motor with the wheel (the saw blade is stationary).

A large number of sharpening machines of various functionality are produced. The most complex and expensive programmable complexes are capable of providing a fully automatic sharpening mode, in which all operations are performed without the participation of a worker.

In the simplest and cheapest models, after installing and securing the saw in a position that provides the required sharpening angle, all further operations. turning the saw around its axis (turning per tooth), feeding for grinding (putting it in contact with the wheel) and controlling the thickness of the metal removed from the tooth. produced by the worker manually. It is advisable to use such simple models at home, when the sharpening of circular saws is episodic.

An example of the simplest machine for sharpening circular saws is the system, the photo of which is shown in the photo below. It consists of two main units. motor with circle (1) and support (2) on which the sharpened saw is mounted. The turning mechanism (3) is used to change the angle of inclination of the blade (when sharpening teeth with a beveled front plane). The screw (4) moves the saw along the axis of the abrasive wheel. This ensures that the required rake angle is set. The screw (5) is used to set in the desired position of the limiter, which prevents the excessive entry of the wheel into the interdental cavity.

Saw blade sharpening process

The saw is installed on a mandrel, clamped using a tapered (centering) sleeve and nut, then set in a strictly horizontal position using a mechanism (3). This ensures the bevel angle of the front plane (ε1) equal to 0 °. For machines for sharpening discs that do not have a built-in angular scale in the tilt mechanism, this is done using a conventional pendulum goniometer. In this case, the horizontal position of the machine should be checked.

By turning the screw (4) of the mechanism that ensures the horizontal movement of the mandrel with the circle, the required front sharpening angle is set. In other words, the saw moves to a position where the front plane of the tooth is firmly attached to the working surface of the wheel.

The engine is turned on and the front plane is sharpened. bringing the tooth into contact with the circle and several movements of the saw back and forth while simultaneously pressing the tooth against the circle. The thickness of the metal to be removed is regulated by the number of sharpening movements and the force of pressing the tooth against the abrasive wheel. After sharpening one tooth, the saw is removed from contact with the wheel, rotated by one tooth and the sharpening operation is repeated. And so on until the marker mark makes a full circle, indicating that all the teeth are sharpened.

Sharpening of a beveled tooth. The difference between sharpening a beveled tooth and sharpening a straight tooth is that the saw must be installed not horizontally, but with an inclination. with an angle corresponding to the bevel angle of the front plane.

The tilt angle of the saw is set using the same pendulum goniometer. First, a positive angle is set (in this case 8 °).

After that, every second tooth is sharpened.

After sharpening half of the teeth, the tilt angle of the saw blade changes from 8 ° to 8 °.

And every second tooth is sharpened again.

Rear sharpening. To sharpen a tooth along the back plane, it is necessary that the saw blade sharpener allows the saw to be installed in such a way that the back plane of the tooth will be in the same plane with the working surface of the abrasive wheel.

If there is no machine for sharpening saw blades

Maintain the required sharpening angles precisely while holding the saw in your hands. an unbearable task even for a person with a unique eye and enviable firmness of hands. The most reasonable thing in this case. make the simplest sharpening device that makes it possible to fix the saw in a certain position in relation to the circle.

The simplest of such devices for sharpening circular saws is a stand, the surface of which is flush with the axis of the grinding wheel. By placing the saw blade on it, you can ensure that the front and back planes of the tooth are perpendicular to the saw blade. And if the upper surface of the stand is movable. by hinging one side and the other. supported by a pair of bolts that can turn in and out. then it can be installed at any inclination, getting the opportunity to sharpen an oblique tooth along the front and back planes.

True, in this case, one of the main problems remains unresolved. keeping the same front and rear sharpening angles. You can solve this problem by fixing the center of the saw relative to the abrasive wheel in the desired position. One way to implement this. make a groove on the surface of the stand for the mandrel on which the saw is installed. Moving the mandrel with a circle along the groove, it will be possible to maintain the required rake angle of the tooth sharpening. But for sharpening circular saws with different diameters or sharpening angles, it must be possible to either move the motor or the stand and the groove with it. Another way to provide the required sharpening angle is simpler, and is to install the stops on the table to fix the disc in the desired position. At the end of the article there is a video demonstrating such a device.

How to know when it’s time to sharpen your circular saw

Sharpen the saw blade only when necessary. It is possible to recognize the onset of such a moment by two clear signs. In particular, urgent sharpening of a circular saw for wood is necessary:

• If a high temperature build-up occurs on a regular basis on the saw guard in the area of ​​the electric motor. In some cases, with such an increase in temperature indicators, smoke is released under the casing.
• With strong pressure on the tool to obtain a good cut during material processing.
• If dark marks appear, traces of carbon deposits on the wood and the characteristic smell of burnt wood. This occurs when the saw teeth are blunt.

What you need to sharpen circular saw blades

First of all, you need to prepare the appropriate accessories that will allow you to properly sharpen the saw blade on wood. It is important to consider the availability of the following tools:

• file;
• assembly vices;
• wooden block;
• colored marker.

How to sharpen circular saws with your own hands

The process of building private houses and various buildings will be quite difficult without the use of a circular saw. It is significantly better than many wood saws, as it surpasses them in accuracy and cleanliness of sawing.

Due to the fact that this tool is actively used, it wears out rather quickly, and therefore sharpening circular saws with your own hands becomes extremely necessary.

Principle and angle of sharpening of circular saw blades

The working part of the circular saw is sharpened at 4 main sharpening corners. They relate to the main technical parameters of the cutting blade, as well as the type of shape of the cutting teeth.

It should be noted that all circular saw teeth are characterized by front (γ), rear (α) angles, as well as the cutting angle of the front and rear surfaces (ε1 and ε2). The value of each specified angle must correspond to the purpose of the sawing devices, the materials to be cut and the direction of sawing.

In particular, the rip saw is sharpened at fairly large rake angles (15 °. 25 °).

Indicators of sharpening of rake corners for cross-cut types are in the range of 5 °. 10 °. Universal options used for processing materials in all types of directions, sharpened at 15 ° as standard.

In this case, the value of the specified angle is also influenced by the fact that the hardness of the cut objects has. Their value has a strict dependence: with a higher hardness of the material that is cut, the cutting teeth should be less sharpened.

According to the main principle of sharpening teeth on a carbide saw blade, it is important to take into account that during long-term operation, the most significant wear processes occur on the upper cutting edges. As a result, with intensive use, their mowing lines can be rounded to 0.3 mm or more. Regarding the tooth planes, it is worth noting that the greatest wear occurs on the front surfaces.

With correct sharpening of the cutting element, such shapes of the cutting edges should be ensured, in which the radius of their rounding does not exceed 0.2 mm. In this regard, it is recommended to perform parallel grinding of metal on the front and back planes of the teeth. The use of this method is considered the most appropriate. It is possible to sharpen only one front plane, but in such cases it takes more time to complete this operation. In addition, the teeth will grind off more quickly, since there is a need to grind off more metal from the front surfaces.

The standard layer for metal grinding is a value of 0.05-0.15 mm.

Varieties of sharpening cutting teeth

For a better understanding of how circular saws are sharpened, it is necessary to study the features and structure of those parts of the tool through which the material is cut. Cutting teeth are the main element involved in sawing wood.

They are made of carbide metal. The cutting teeth consist of 4 working flat surfaces: front (a), rear (b) and two side planes (c), which have an auxiliary role. By means of one main (1) and two additional (2 and 3) cutting edges, the mowing line intersects, each specified working plane.

Depending on its configuration, a circular saw can have different types of cutting teeth:

• Straight type of teeth. Often used for fast rip sawing. Do not have perfect cut quality.
• Beveled (oblique) type of teeth. They have a characteristic corner cut on the right and left back surfaces. In some cases, the blades have teeth with different sides of the bevel, which alternate around the entire circumference of the saw. Using such discs, you can cut wood, chipboard and various plastics. Large bevel angle ensures high-quality cuts without chipping at the cutting edge.
• Trapezoidal type of teeth. The cutting surfaces have a trapezoidal cross-section. This configuration allows you to work without bluntness for a long period of time. Often the disc has straight teeth, which alternate with trapezoidal ones. In such cases, the trapezoidal element plays a major role in rough sawing, while the straight tooth type is used for finishing.
• Conical type of teeth. They have a conical appearance. As a rule, they perform an auxiliary function for preliminary cuts on the laminate. The tapered type of teeth is used for processing the specified floor covering. This saw prevents chipping in the material, as is often the case with the main saw.

How to sharpen a circular saw with your own hands

You can sharpen the saw at home completely on your own. For these purposes, there is no need to visit a workshop to use a specialized grinding machine or to purchase one. It is quite expensive, and is rarely used for sharpening, unless of course you plan to use it for large production purposes.

But holding the saw blades in your hands while sharpening the teeth with a grinding wheel is not the best solution. A circular disc is not a drill, it is much larger. No hardness of hands and an excellent eye will allow you to sharpen so that the cutting elements are sharp enough and suitable for effective use. To do this, you need to provide the simplest fixing device.

To hold the toothed circular circle in the desired position relative to the plane of the sharpening tool, you can use the most ordinary flat stand.

The position of its surface should correspond to the level of the axes on the rear disc. The gear wheel is placed on a support so that the sharpened plane of the tooth is perpendicular to the saw blade. To sharpen beveled teeth on the front and rear surfaces, you need to provide movable hinges in this device.

But in such cases, it is quite difficult to maintain the same values ​​of the front and rear sharpening angles of the tool. To eliminate this problem, it is necessary to firmly fix the center of the saw in accordance with the desired position in relation to the grinding wheel. This is done using grooves for the mandrel, which is mounted on a stand with the sharpened saws on it, or by installing a special stop on the stand, which will fix the saw blade according to the required angle to the abrasive stone.

If you adhere to all the requirements that apply to sharpening a carbide circular saw, then this tool will work as efficiently as possible over a long period of time.

Required tools

With your own hands, discs for a circular plate can only be sharpened with special tools. There is also a machine that allows you to automate the process, make it more efficient.

To carry out work on sharpening a disc with your own hands, you can use the following tools:

• assembly vise;
• file;
• block of wood.

A circular saw sharpener can also be used, which does not require the above tools.

Sharpening A Carbide Saw Blade By Hand

Principles and angles of sharpening circular saws

The saw has four main corners of the saw blade sharpening along the working part. The angles in question, as well as the shape of the tooth itself, can be called the main operational characteristics. Each tooth can be characterized as follows:

• front and back angle;
• cutting angles of the front and rear surfaces.

The values ​​of the above parameters depend on the purpose of the sawing device, the type of workpiece material.

Circular saw tooth surfaces

According to the above parameters, several saws can be distinguished:

• for slitting. In this case, the rake angle should be between 15 ° and 25 °.
• when performing cross-cutting, the indicator in question should be from 5 ° to 10 °.
• universal version, it is recommended to sharpen at an angle of 15 °.

The type of material to be processed also determines what characteristics the tooth should have. Generally, the harder the material, the more difficult it is to machine. That is why it is recommended to sharpen the cutting teeth to a lesser extent.

With prolonged use of a carbide saw, significant wear occurs at the topmost cutting edge. When considering the plane of the tooth, it is worth noting that more wear is on the front surface.

Types of circular saw teeth

Sharpening circular saws at home

You can sharpen the saw with your own hands without using a special sharpening machine, which has a high cost and is rarely used for its intended purpose due to the use of carbide material when creating a cutting edge. However, you cannot just hold the circle in your hands, since you need to achieve certain cut parameters to ensure the required performance indicator.

To fix the gear wheel in a strictly specified position, an ordinary flat stand is used. It has the following features:

• The surface of the flat stand must be level with the axis of the grinding wheel.
• Place the gear wheel on a stand so that the sharpening plane is perpendicular to the saw blade.
• The device in question for teeth located at a certain angle is equipped with a swivel joint.

The considered device allows you to fix the workpiece in relation to the used abrasive material. With the help of a colored marker, marking lines are drawn, which allow you to select the correct angle. A vice is also needed, in which the created fixation device is attached.

Sharpening a circular saw with your own hands

The method of sharpening a circular disc depends on the availability of the necessary tools at hand. If it is not possible to use a special machine for this purpose, then a good result can be achieved with a minimum set in the form of a file, a vice and a pair of wooden blocks to secure the disc.

Circular disk sharpening scheme on the machine.

It will be more convenient to sharpen the part if you do not remove it from the machine, but first you must remember to disconnect the equipment from the power supply. To begin with, you need to ensure that the disc is securely fixed using wooden blocks placed under it on both sides. A toothed disc, separate from the saw, is placed in a vice, clamped with wooden wedges. It is better to mark the first tooth, from which processing will begin, with a bright marker so as not to perform actions on the second circle.

You should start work from the back surface. When sharpening teeth, it is necessary to control the uniformity of the applied forces as much as possible and try to maintain the same number of file movements in each case. In order to train your hand in this action, you can use an old hacksaw to start with, which you will not mind spoiling.

Checking the quality of the sharpened disc is carried out during a trial cut. Uneven material advance and extraneous noise may indicate that the teeth are at different levels. This can be detected by bringing the marker close to the cutting edge of the blade and making it a full turn in the opposite direction of normal operation. Marked teeth require re-filing.

Manual way

Special saw blade sharpening machines are rarely used in a domestic environment because their cost is high. Therefore, in the absence of such a device, you can cope with sharpening with improvised devices, for example, an angle grinder. In this case, it is forbidden to hold the circle in your hands without fixing it with anything. Otherwise, it will not be possible to achieve a sufficient cutting angle for further work with the material.

To securely fix the circle in the correct position, use a flat stand.

• the surface of the stand coincides with the level of the axis of the grinding wheel;
• on it, the gear wheel is placed in such a way that the sharpening plane becomes perpendicular to the saw blade;
• the design of the device is complemented by a swivel joint.

The stand will help you to comfortably position the saw blade for cutting in relation to the abrasive material. Before starting work, clear markings are carried out. A colored marker is used for this. They draw a mowing line, which will allow the element to be sharpened at the desired angle. The vise will help secure the disc to the surface.

Video of sharpening a circular saw blade angle grinder:

Sharpening principles and angles

There are four main sharpening corners at the edges of the saw. Together with the shape of the tooth, they can be the main performance characteristics of the tool. The following are used to describe each tooth:

• Front and back angle.
• Cut angles of the front and back surfaces.

These characteristics may depend on the type and weight of the circular saw, its purpose, as well as the density of the specific surface.

Sharpening angles in the diagram

Based on the parameters indicated above, all circulars can be divided into several types:

• For slotting longitudinal holes. A 15 to 25 degree rake angle should be used for this task.
• For cross-cutting. In this situation, the rake angle can vary from 5 to 10 degrees.
• Universal sharpening. Saws are sharpened at an angle of 15 degrees for any operation.

The size of the sharpened angle is not only determined by the direction of movement of the saw, it is also related to the material of the workpiece. When cutting through very hard materials, the smallest angle should be chosen. To work with softer products, the angle increases.

Important! If a carbide saw has been used long enough, maximum wear will be seen at the top cutting edge. A detailed examination of the plane of the tooth shows that the anterior surface of the material suffers the most.

How to sharpen a circular saw blade correctly and at what angle

The use of circular saws is especially common in construction. Most of the work requires cuts and changes in the shape and size of the finished materials. The circular saw helps you tackle these tasks quickly and get quality results. But the instrument is not capable of serving forever, sooner or later it may become dull. It is for this that you need to know exactly how you can sharpen saw teeth in a domestic environment.

How to sharpen: basic methods

There are two methods available for sharpening circular saws. manual and machine. In order to sharpen the disc correctly at home, you need to take into account some of the nuances.

Tools

It is allowed to sharpen the saw with your own hands only when using special devices. For this, there is a grinding machine that helps to carry out the process on an automatic machine, and not manually. Then the result becomes more accurate.

In addition, other improvised devices are used for sharpening:

• Mounting vise;
• File;
• Piece of wood.

You will not be able to replace the listed devices. If at least one of them is not available, then sharpening will not work.

How to properly sharpen a circular saw blade

Saw blades must be sharpened regularly to avoid damage to the building material. We will tell you how to properly sharpen a saw blade with and without solders, what equipment and tools to use.

The disc tool for sawing wood is always useful in construction. The circular saw is convenient in that it allows you to quickly cut the material with minimal effort and time. As for the quality of the cut, we can say that it is perfect, but only when the saw is in good working order and well sharpened. Otherwise, it is even dangerous to work with such a tool, so you should sharpen the circular saw.

Determining the need for a sharpening operation is not difficult: a blunt tool cuts the workpiece poorly, which immediately catches the eye. There are two options here: either send the disc to the workshop, which is not always beneficial in terms of time and money, or sharpen the circular saw with your own hands. This may seem daunting at first glance. But if you delve into the essence of the saw device in more detail, it will not be difficult to perform maintenance of the tool at home.

When to sharpen a circular saw

There are very definite signs by which one can judge the state of the instrument. Sharpening saws is necessary when the following is clearly manifested:

• During operation, smoke appears, a specific smell of burnt wood, the casing covering the saw teeth begins to heat up quickly.
• When moving the tool along the workpiece, significant efforts must be made to push the saw forward.
• After cutting the material and visual inspection of the sawn edge, black carbon deposits or a lot of chips, fiber scoring, chipped areas are visible.
• A close examination of the saw teeth with a magnifying glass shows that the cutting parts are not sharp, but rounded edges.

All this requires an immediate cessation of work, otherwise there is a great risk of damage to the material and wear of the circular saw to such a state when sharpening will no longer help it.

How can you sharpen a circular saw

• Special wheels for sharpening saws, made on the basis of diamond abrasives.
• A regular file for sharpening a saw, but you also need to have a vise to secure the saw and a block of wood to use as a guide.
• Processing on professional equipment is the fastest and highest quality way of sharpening, but it requires large material costs for purchasing a tool.

Types of circular saw teeth setting

The complexity of the wiring process is due to the need to move the teeth to the side at the same distance. This can be achieved by using a factory set circulating saw setter. Each tooth should be started from the middle of its size. For wood materials of different density, the degree of setting the teeth should be different, but without going into details, we can say that they are bred wider for sawing soft species than for hard ones.

There are three main wiring methods:

• Stripping type wiring. This method boils down to the fact that the tooth after two remains in its place without change, the rest are rejected in different directions. This saw preparation is good for working with solid wood.
• A variant of the classic setting, when the saw teeth alternately move to the right and then to the left. This versatile method can be used for almost all types of saws.
• The so-called wavy layout, a distinctive feature of which is the retraction of the teeth not at a strictly defined distance from the center, but at different distances with a deviation of 0.3-0.7 millimeters.

Sharpening saws do it yourself at home

Attention! To sharpen circular saws with your own hands, it is desirable to have certain skills in sharpening the tool. If there are none, at least practice on emery, sharpening an ordinary knife.

When working with a disc, the main thing is not to spoil the cutting surface, and this can easily happen if the hand trembles, the feed angle is violated. In order to avoid negative consequences, you should study the sharpening methods, and then everything will turn out right. Distinguish between a manual method of restoring cutting elements of a circular saw and a method using sharpening equipment.

General rules for sharpening a circular saw

• The main edges are processed first of all, of which the front wears out more.
• In extreme cases, with severe wear of the side faces, they are corrected.
• At a time, remove no more than 0.15 millimeters of the saw metal thickness.
• When finishing the edges with an electric tool, overheating of the metal is not allowed, in which case its properties deteriorate.
• To ensure the maximum service life of the saw, when it can be sharpened up to 30 times, both edges should be sharpened: both the front and the back. removing the same amount of metal.
• It is not allowed to sharpen circular saws with tools that are not intended for this, for example, an angle grinder and a disc for cutting metal.

After carrying out the basic sharpening operations, you can finalize the teeth with fine sandpaper. The quality control of the sharpening of the tool takes place in working conditions. If everything is in order, the cutting of the material will be clean, smooth, without visible defects and blackening.

Manual way

It is possible to independently sharpen the teeth by hand using a file, so that it is of high quality, if they do not have a bevel, that is, the surface of the front face is perpendicular to the surface of the blade. The process looks like this:

• A block is harvested from dense wood with a section of somewhere 50×50 mm and a length of 100 mm. The sides of the bar should be located strictly perpendicular to each other.
• Mark with a marker any tooth that will be reportable and the first to be processed.
• The saw blade is clamped in a vice together with a bar so that the front edge of the workpiece is flush and in the same plane with the surface of the bar (in this case, the bar acts as a guide for the file).
• A thin file (its thickness should allow it to fit freely into the cavity between adjacent teeth) is applied to the surface of the tooth to be treated and at the same time to the bar and methodical movements back and forth, sharpening is carried out.
• This is how each tooth is gradually sharpened, monitoring the condition of the bar and, when working out its surface, slightly shifting the plane.